Ambilight setup, why do we need (we think) extra electronics in there like capacitors/resistors, experiences thoughts and explanations

hello folks,

after being here for quite a time i see that people intend to use extra electronics in his/hers Ambilight setup.

my question is why,

don't get me wrong, each to his own.

but....

I never understood why the Ambilight guys think they need a capacitor soldered between the +5volts line and GND on the strip.

the only thing a capacitor does in this typical setup is "buffering" and storing power when its needed, this capacitor used ( in microfarrad) is so tiny that it only works for milli seconds

that is if it even works at all. ( do you know its actually doing something at all, or you can do without?)

in my world/eyes and out of the engineeringfield, if you have a powerfull PSU that delivers a steady/clean rectified AC to DC then the use of extra capacitors isn't necessary

the good quality PSU is more then capable to be "powerdrained" without having a problem in rectifier circuit.

and then the resistor in the dataline before connected to the strip ( mostly 3 line strips)

the resistor in series is only meant to protect the first LED in the strip and only if the strip is powered from one side this has use.

for the rest of it it does absolutely nothing.

i am talking about this>>>

power from both sides ( the ledstrip) is the way to go in that setup,

less electronics is always better then a lot. Why use that capacitor is it really really necessary??

in my eyes, when u need to solder capacitors between the powerlines then something isn't already quite right from the start..

my only two cents. ( or prove me wrong, i might learn something)

note; i am not using them no capacitor/resistor

i 've read a story when only with starting of the (bad quality) PSU spikes in the voltage will occur and possibility is without using the capacitor > can damage your ledstrip.

but thats only when booting up the powersupply.

when powersupply already runs and then ledstrip is powered up nothing can happen i would say...

oh, and also don't forget to fuse correctly like davieboy explained in his topic, RE: Protect you Build because this can also mean a way to high current ( unwanted) trough your electronics.

D34DC3N73R

thanks for the input, i know that site ( looked in there before) from beginning with ambilight project.

The resistor data line surge i get, i think its also mostly for 3 -line strips that only have 1 data line.

i think also for Raspi you don't need them ( can't hurt if used) because dataline output isn't higher than 3,3 volts.

the capacitor story all comes back to the use of a weak/not steady powersupply and/or not clean and rectified enough.

that said;

-i am not convinced ( yet) about the capacitor

-i am about the resistor, but only if used in a MCU/controller thats not a Raspi.

i think and thats the mainreason why they will repeat that, most people are not experienced in electronics and buy the cheapest stuff from Amazon or AliExpress they can find like powerbricks and such.., if you use that stuff then chance is big you will fry the neopixels strip from them and they dont want that of course.

so ( how i see it) its a precausion to use that capacitor to RULE OUT bad PSU thats on the market.

D34DC3N73R

i am a oldschool guy, i think that we have come far into electronics from 30 years ago untill now.

PSU's thats fabricated now ( the better ones/brands) are way way better than 20/30 years ago, they are all electronic, have safety in them and switch off if it detects mallfunction and/or to high power drainage like shortcutting.

So to be short; no it can't hurt to use the capacitors of course not.

but you can do without is my 2 cents.

i never used capacitors/resistor in my build and it runs flawless for already 1,5 years.

Quote from D34DC3N73R

To summarize, yes, you'll probably be fine without using caps and a resistor

good argument, but..

I think that a big brand like Meanwell ( the real one) where we do purchase a lot at the company, cannot afford bad quality.

A big brand like that can not take the chance into a "bad production or cheaper costs" , the professional installations depend on hassle free and no mallfunction environment. If it was the case that a PSU will die fast then they get a bad reputation fast also

so i will stand by this, most problems with builds/setups if its ambilight or something else will most the time come back to the person who build it and has a flaw in the build. Its not the PSU but

• bad connections in general
• gauge of wire not thich enough, has more resistance in wire like AWG18 ( its only 1mm thick)
• not soldered joints/PINS or connections in general
• Grounding trough GND pins/ledstrip/PSU isn't done properly or not at all.
• using two diffrent powersources and not grounded correctly to each other
• PSU is a cheap knock off or even worse powerbrick" with no earth connection to powergrid.
• PSU is bad, to much AC running trough DC signal and not rectified properly ( believe me that happens a lot )
• the list goes on and on.

especially for low voltage and high currents soldered joints become really important to reduce resistance into the joints as much as possible.

so you see before this is all not correct you can use as much capacitor as you want but you never get the results you are hoping for.

thatswhy i myself am not a big believer into adding electronics that shouldn't be necessary in the first place.

call me old fashion, and... each to his own.

advice is free.

Quote from TPmodding

if you have a look at the sk6812, you would need for every led a cap...

1 microfarrad each LED, i wonder what it does and >> is it also implemented into the strip type of the sk6812?

i think it should be there to flatten out the curve . if it even excist > to protect the led and also make it possible to run at lower voltage, i think thats the mainreason they implement it.

• just to be safe
• make it possible run on 3,5 volts ( capacitor works as a storage container for power needed)

something like that, still i am convinced if i see the schedule that the led will run on 5 volts without the c2 104 cap.

And in general when you think about it then if the capacitor is needed into the schematics if you are using the led without a strip.

whats the purpose then to use a 1000 microfarrad 16volts capacitor for the whole line at the beginning?

its impossible for that capacitor to hold and flatten out a curve for all the leds simultaniously ( because they are mounted in voltage parallel, so equal 5 volts applied)

Quote from Mike72

especially for cheap high current china power supplies. Maybe a little oversized...

Also, APA102 never worked properly without a level shifter in my setups.

hahaha something similar i used in car-hifi installations, the 1,5 Farrad cap > carefull with installments! always use a lightbulb in series to load.

Really never worked? i made already 3 setups now,

• ws2801 first build
• apa102 for myself, second build
• apa102 for a friend

not any of the builds needed level shifter/caps or resistors.

maybe i am just lucky